1. Field of the Invention
The present invention relates to the field of ink jet recording. More particularly, the invention relates to an ink tank retaining in it a plurality of different kinds of ink together, and relates to an ink jet cartridge.
2. Related Background Art
For a calculator, a wordprocessor, facsimile equipment, a copying machine, a printer, or various other equipment, for example, an ink jet recording apparatus (hereinafter referred to as an ink jet printer) is widely used as means for recording on a recording medium such as a recording sheet, because not only it can record at high speeds with a lesser amount of noises, but also, it can record color images easily.
An ink tank used for the ink jet printer described above is to supply ink to the ink jet recording head that discharges ink from its ink discharge ports for recording. Here, an ink tank having plural ink retaining units in it may be used in some cases when plural kinds of ink are used for color printing in particular.
Also, in recent years, from the viewpoint of making the apparatus smaller, or the like, an ink jet cartridge, which can form an ink tank integrally with a recording head, has become the main current of use. Such ink jet cartridge is detachably mountable on a recording apparatus. The cartridge can be classified into the one structured to keep its recording head unit and an ink tank to be integrated at all times, and the one structured to have its recording head unit and an ink tank formed separately and put them together at the time of use. In either mode, a structure is known to form a plurality of ink retaining units in an ink tank for recording in colors.
For an ink tank or an ink jet cartridge used for color recording as described above, it is usually arranged to fill in either of them with the different kinds of color ink each in the same amount, and in accordance with applicable printing data, each color ink is discharged from the ink discharge ports as designated. For example, three kinds of color ink, yellow (Y), magenta (M), and cyan (C), are prepared, respectively, and when a printer performs a multiple color printing in accordance with the applicable color printing data, the designated colors are appropriately selected for printing from among the three kinds of ink described above depending on the contents of such printing data.
Compared to the case where each individual ink tank is used for each color, the structure described above has an advantage that there is no possibility of mounting an ink tank of different color erroneously, while the ink tank can be provided at lower costs because there is no need for the provision of any particular arrangement to prevent erroneous mounting or the like. Also, for an ordinary use, the average consumption of Y, M, and C is not extremely different from each other. Therefore, with the structure thus arranged, ink remainders do not present any problem that may require extremely severe attention.
Nevertheless, in accordance with the prior art described above, the ink tank becomes no longer usable if only ink of a specifically designated color is used for printing and ink of such color is completely consumed, while ink of the other colors still remains in the ink tank. Here, therefore, the problem of ink remainders still exists.
As one solution of a problem of the kind, the capacity of each ink chamber is made different, larger or smaller, depending on the anticipated consumption of each ink when arranging a plurality of chambers to retain a plurality of color ink, respectively, as disclosed in Japanese Patent Publication No. 2-5587.
However, if there are included many of the patterns that require only a specifically designated color for printing, it is necessary to arrange each chamber differently, larger or smaller, corresponding to the anticipated consumption of each ink as the case may be each time. An arrangement of the kind leads to increased costs inevitably. This is not economical after all.